Golang Tx.Metadata方法代码示例

// maybeCreateIndexes determines if each of the enabled indexes have already
// been created and creates them if not.
func (m *Manager) maybeCreateIndexes(dbTx database.Tx) error {
	indexesBucket := dbTx.Metadata().Bucket(indexTipsBucketName)
	for _, indexer := range m.enabledIndexes {
		// Nothing to do if the index tip already exists.
		idxKey := indexer.Key()
		if indexesBucket.Get(idxKey) != nil {
			continue
		}

		// The tip for the index does not exist, so create it and
		// invoke the create callback for the index so it can perform
		// any one-time initialization it requires.
		if err := indexer.Create(dbTx); err != nil {
			return err
		}

		// Set the tip for the index to values which represent an
		// uninitialized index (the genesis block hack and height).
		genesisBlockHash := m.params.GenesisBlock.BlockSha()
		err := dbPutIndexerTip(dbTx, idxKey, &genesisBlockHash, 0)
		if err != nil {
			return err
		}
	}

	return nil
}

// DbPutBestState uses an existing database transaction to update the best chain
// state with the given parameters.
func DbPutBestState(dbTx database.Tx, bcs BestChainState) error {
	// Serialize the current best chain state.
	serializedData := serializeBestChainState(bcs)

	// Store the current best chain state into the database.
	return dbTx.Metadata().Put(dbnamespace.StakeChainStateKeyName, serializedData)
}

// TxRegionsForAddress returns a slice of block regions which identify each
// transaction that involves the passed address according to the specified
// number to skip, number requested, and whether or not the results should be
// reversed.  It also returns the number actually skipped since it could be less
// in the case where there are not enough entries.
//
// NOTE: These results only include transactions confirmed in blocks.  See the
// UnconfirmedTxnsForAddress method for obtaining unconfirmed transactions
// that involve a given address.
//
// This function is safe for concurrent access.
func (idx *AddrIndex) TxRegionsForAddress(dbTx database.Tx, addr dcrutil.Address, numToSkip, numRequested uint32, reverse bool) ([]database.BlockRegion, uint32, error) {
	addrKey, err := addrToKey(addr, idx.chainParams)
	if err != nil {
		return nil, 0, err
	}

	var regions []database.BlockRegion
	var skipped uint32
	err = idx.db.View(func(dbTx database.Tx) error {
		// Create closure to lookup the block hash given the ID using
		// the database transaction.
		fetchBlockHash := func(id []byte) (chainhash.Hash, error) {
			// Deserialize and populate the result.
			return dbFetchBlockHashBySerializedID(dbTx, id)
		}

		var err error
		addrIdxBucket := dbTx.Metadata().Bucket(addrIndexKey)
		regions, skipped, err = dbFetchAddrIndexEntries(addrIdxBucket,
			addrKey, numToSkip, numRequested, reverse,
			fetchBlockHash)
		return err
	})

	return regions, skipped, err
}

// dbFetchTxIndexEntry uses an existing database transaction to fetch the block
// region for the provided transaction hash from the transaction index.  When
// there is no entry for the provided hash, nil will be returned for the both
// the region and the error.
func dbFetchTxIndexEntry(dbTx database.Tx, txHash chainhash.Hash) (*database.BlockRegion, error) {
	// Load the record from the database and return now if it doesn't exist.
	txIndex := dbTx.Metadata().Bucket(txIndexKey)
	serializedData := txIndex.Get(txHash[:])
	if len(serializedData) == 0 {
		return nil, nil
	}

	// Ensure the serialized data has enough bytes to properly deserialize.
	if len(serializedData) < 12 {
		return nil, database.Error{
			ErrorCode: database.ErrCorruption,
			Description: fmt.Sprintf("corrupt transaction index "+
				"entry for %s", txHash),
		}
	}

	// Load the block hash associated with the block ID.
	hash, err := dbFetchBlockHashBySerializedID(dbTx, serializedData[0:4])
	if err != nil {
		return nil, database.Error{
			ErrorCode: database.ErrCorruption,
			Description: fmt.Sprintf("corrupt transaction index "+
				"entry for %s: %v", txHash, err),
		}
	}

	// Deserialize the final entry.
	region := database.BlockRegion{Hash: &chainhash.Hash{}}
	copy(region.Hash[:], hash[:])
	region.Offset = byteOrder.Uint32(serializedData[4:8])
	region.Len = byteOrder.Uint32(serializedData[8:12])

	return &region, nil
}

// DbLoadAllTickets loads all the live tickets from the database into a treap.
func DbLoadAllTickets(dbTx database.Tx, ticketBucket []byte) (*tickettreap.Immutable, error) {
	meta := dbTx.Metadata()
	bucket := meta.Bucket(ticketBucket)

	treap := tickettreap.NewImmutable()
	err := bucket.ForEach(func(k []byte, v []byte) error {
		if len(v) < 5 {
			return ticketDBError(ErrLoadAllTickets, fmt.Sprintf("short "+
				"read for ticket key %x when loading tickets", k))
		}

		h, err := chainhash.NewHash(k)
		if err != nil {
			return err
		}
		treapKey := tickettreap.Key(*h)
		missed, revoked, spent, expired := undoBitFlagsFromByte(v[4])
		treapValue := &tickettreap.Value{
			Height:  dbnamespace.ByteOrder.Uint32(v[0:4]),
			Missed:  missed,
			Revoked: revoked,
			Spent:   spent,
			Expired: expired,
		}

		treap = treap.Put(treapKey, treapValue)
		return nil
	})
	if err != nil {
		return nil, ticketDBError(ErrLoadAllTickets, fmt.Sprintf("failed to "+
			"load all tickets for the bucket %s", string(ticketBucket)))
	}

	return treap, nil
}

// DbPutDatabaseInfo uses an existing database transaction to store the database
// information.
func DbPutDatabaseInfo(dbTx database.Tx, dbi *DatabaseInfo) error {
	meta := dbTx.Metadata()
	subsidyBucket := meta.Bucket(dbnamespace.StakeDbInfoBucketName)
	val := serializeDatabaseInfo(dbi)

	// Store the current database info into the database.
	return subsidyBucket.Put(dbnamespace.StakeDbInfoBucketName, val[:])
}

// dbPutIndexerTip uses an existing database transaction to update or add the
// current tip for the given index to the provided values.
func dbPutIndexerTip(dbTx database.Tx, idxKey []byte, hash *chainhash.Hash, height uint32) error {
	serialized := make([]byte, chainhash.HashSize+4)
	copy(serialized, hash[:])
	byteOrder.PutUint32(serialized[chainhash.HashSize:], height)

	indexesBucket := dbTx.Metadata().Bucket(indexTipsBucketName)
	return indexesBucket.Put(idxKey, serialized)
}

// DbDropNewTickets drops new tickets for a mainchain block data at some height.
func DbDropNewTickets(dbTx database.Tx, height uint32) error {
	meta := dbTx.Metadata()
	bucket := meta.Bucket(dbnamespace.TicketsInBlockBucketName)
	k := make([]byte, 4)
	dbnamespace.ByteOrder.PutUint32(k, height)

	return bucket.Delete(k)
}

// dbFetchBlockIDByHash uses an existing database transaction to retrieve the
// block id for the provided hash from the index.
func dbFetchBlockIDByHash(dbTx database.Tx, hash chainhash.Hash) (uint32, error) {
	hashIndex := dbTx.Metadata().Bucket(idByHashIndexBucketName)
	serializedID := hashIndex.Get(hash[:])
	if serializedID == nil {
		return 0, errNoBlockIDEntry
	}

	return byteOrder.Uint32(serializedID), nil
}

// DbPutBlockUndoData inserts block undo data into the database for a given height.
func DbPutBlockUndoData(dbTx database.Tx, height uint32, utds []UndoTicketData) error {
	meta := dbTx.Metadata()
	bucket := meta.Bucket(dbnamespace.StakeBlockUndoDataBucketName)
	k := make([]byte, 4)
	dbnamespace.ByteOrder.PutUint32(k, height)
	v := serializeBlockUndoData(utds)

	return bucket.Put(k[:], v[:])
}

// DbPutNewTickets inserts new tickets for a mainchain block data into the
// database.
func DbPutNewTickets(dbTx database.Tx, height uint32, ths TicketHashes) error {
	meta := dbTx.Metadata()
	bucket := meta.Bucket(dbnamespace.TicketsInBlockBucketName)
	k := make([]byte, 4)
	dbnamespace.ByteOrder.PutUint32(k, height)
	v := serializeTicketHashes(ths)

	return bucket.Put(k[:], v[:])
}

// DbFetchBestState uses an existing database transaction to fetch the best chain
// state.
func DbFetchBestState(dbTx database.Tx) (BestChainState, error) {
	meta := dbTx.Metadata()
	v := meta.Get(dbnamespace.StakeChainStateKeyName)
	if v == nil {
		return BestChainState{}, ticketDBError(ErrMissingKey,
			"missing key for chain state data")
	}

	return deserializeBestChainState(v)
}

// dbRemoveTxIndexEntry uses an existing database transaction to remove the most
// recent transaction index entry for the given hash.
func dbRemoveTxIndexEntry(dbTx database.Tx, txHash chainhash.Hash) error {
	txIndex := dbTx.Metadata().Bucket(txIndexKey)
	serializedData := txIndex.Get(txHash[:])
	if len(serializedData) == 0 {
		return fmt.Errorf("can't remove non-existent transaction %s "+
			"from the transaction index", txHash)
	}

	return txIndex.Delete(txHash[:])
}

// dbFetchBlockHashBySerializedID uses an existing database transaction to
// retrieve the hash for the provided serialized block id from the index.
func dbFetchBlockHashBySerializedID(dbTx database.Tx, serializedID []byte) (chainhash.Hash, error) {
	idIndex := dbTx.Metadata().Bucket(hashByIDIndexBucketName)
	hashBytes := idIndex.Get(serializedID)
	if hashBytes == nil {
		return chainhash.Hash{}, errNoBlockIDEntry
	}

	var hash chainhash.Hash
	copy(hash[:], hashBytes)
	return hash, nil
}

// DbCreate initializes all the buckets required for the database and stores
// the current database version information.
func DbCreate(dbTx database.Tx) error {
	meta := dbTx.Metadata()

	// Create the bucket that houses information about the database's
	// creation and version.
	_, err := meta.CreateBucket(dbnamespace.StakeDbInfoBucketName)
	if err != nil {
		return err
	}

	dbInfo := &DatabaseInfo{
		Version:        currentDatabaseVersion,
		Date:           time.Now(),
		UpgradeStarted: false,
	}
	err = DbPutDatabaseInfo(dbTx, dbInfo)
	if err != nil {
		return err
	}

	// Create the bucket that houses the live tickets of the best node.
	_, err = meta.CreateBucket(dbnamespace.LiveTicketsBucketName)
	if err != nil {
		return err
	}

	// Create the bucket that houses the missed tickets of the best node.
	_, err = meta.CreateBucket(dbnamespace.MissedTicketsBucketName)
	if err != nil {
		return err
	}

	// Create the bucket that houses the revoked tickets of the best node.
	_, err = meta.CreateBucket(dbnamespace.RevokedTicketsBucketName)
	if err != nil {
		return err
	}

	// Create the bucket that houses block undo data for stake states on
	// the main chain.
	_, err = meta.CreateBucket(dbnamespace.StakeBlockUndoDataBucketName)
	if err != nil {
		return err
	}

	// Create the bucket that houses the tickets that were added with
	// this block into the main chain.
	_, err = meta.CreateBucket(dbnamespace.TicketsInBlockBucketName)
	if err != nil {
		return err
	}

	return nil
}